Patents by Inventor David H. Selfors

David H. Selfors has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20210234492
    Abstract: Power tools including a housing, a motor, a power circuit supplying operating power to the motor through a triac, a speed sensor configured to detect a speed of the motor, a speed selector, and an electronic processor. The electronic processor is configured to determine a selected speed and set a present conduction angle of the triac to an initial conduction angle corresponding to the selected speed. The electronic processor is also configured to determine whether the speed is decreasing and determine whether the present conduction angle is below a maximum conduction angle corresponding to the selected speed when the speed is decreasing. The electronic processor is further configured to increase the present conduction angle when the present conduction angle is below the maximum conduction angle and maintain the present conduction angle at the maximum conduction angle when the present conduction angle is at or above the maximum conduction angle.
    Type: Application
    Filed: April 15, 2020
    Publication date: July 29, 2021
    Inventors: Brian Trump, David H. Selfors
  • Patent number: 10486281
    Abstract: A power tool includes a motor, a power circuit coupled to the motor, and a speed sensor coupled to the motor. The power circuit provides power to the motor. The speed sensor detects a position of the motor. The power tool also includes an electronic processor coupled to the motor and the speed sensor. The electronic processor is configured to receive an output signal from the speed sensor indicative of a measured speed of the motor at a first time, determine a cumulative value based on the measured speed of the motor, and interrupt power from the power circuit to the motor when the cumulative value exceeds an accumulator threshold.
    Type: Grant
    Filed: December 14, 2016
    Date of Patent: November 26, 2019
    Assignee: MILWAUKEE ELECTRIC TOOL CORPORATION
    Inventors: David H. Selfors, Brian Trump
  • Publication number: 20170170774
    Abstract: A power tool includes a motor, a power circuit coupled to the motor, and a speed sensor coupled to the motor. The power circuit provides power to the motor. The speed sensor detects a position of the motor. The power tool also includes an electronic processor coupled to the motor and the speed sensor. The electronic processor is configured to receive an output signal from the speed sensor indicative of a measured speed of the motor at a first time, determine a cumulative value based on the measured speed of the motor, and interrupt power from the power circuit to the motor when the cumulative value exceeds an accumulator threshold.
    Type: Application
    Filed: December 14, 2016
    Publication date: June 15, 2017
    Inventors: David H. Selfors, Brian Trump